PERSISTENCE OF SOME WEED SPECIES FROM WHEAT (TRITICUM AESTIVUM L.) MONOCULTURE VIA SOIL SEED RESERVES

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1 Pk. J. Bot., 44(4): , 1. PERSISTENCE OF SOME WEED SPECIES FROM WHEAT (TRITICUM AESTIVUM L.) MONOCULTURE VIA SOIL SEED RESERVES SEEMA MAHMOOD *, ASMA HUSSAIN AND SAEED AHMAD MALIK Institute of Pure n Applie Biology, Bhuin Zkriy University, Multn * Corresponing uthor s e-mil: rseempk@gmil.om Astrt The reltionship etween soil see reserves n egree of infesttion y ommon wee speies (Aven ftu L., Convolvulus rvensis L., Cyperus rotunus Pers., Fumri prviflor Lmk., Phlris minor Rit. n Solnum nigrum L.) ws ssesse for from five whet fiels. Soil smpling ws rrie out efore sowing seson in fiels where whet rop ws grown. Soil from two profiles (-8 n 8-1m) ws tken from five sites within eh fiel n see nk sie ws estimte vi seeling emergene. A onsierle numer of vile wee sees of the speies were quntifie from oth soil profiles. More vile sees were foun in the lower soil profile thn the surfe lyer. C. rotunus h the gretest see nk sie followe y C. rvensis, F. prviflor n A. ftu, respetively. S. nigrum h the lowest vlues for the ttriute. The stuy inite tht see reserves of these speies n e mjor soure of wee infesttion in whet fiels. It is likely tht sees re trnsferre to the surfe lyer y tillge n give rise new wee popultion tht use infesttion. Moreover, see popultion seems to e emogrphilly well pte through feunity, see sie n longer viility. The stuy suggeste n integrte pproh for wee mngement n ontrol to minimie yiel losses prtiulrly in situtions where wee speies persist through soil see reserves. Introution The onept of wees proly originte with the strt of griulture (Mrwt et l., 1). Wees re unwnte guests in griulturl fiels invite y mngement eisions tht efy nture s priniples (Lemerle et l., 199; Cousens, 1996; Hrtler, 3). Wees re eviene of nture struggling to ring out eologil suession s moern rop griulture is hrterie y lrge reges of single plnt type ompnie y high perentge of re groun- n iel environment for nnul wees to prosper in the first stge of suession (Christensen & Heisel, 1998; Hrtler, 3). Furthermore, stirring soil with tillge retes onitions enourging for wee germintion n survivl (Hrtler, 4; Gul et l., 11). As onsequene, wees negtively ffet rop proution effiieny in severl wys inluing reue yiels, hrvest effiieny n ontriuting to future prolems through wee see proution (Smith & Levik, 1974; Cousens, 1996; Lemerle et l., 1). Wee see nks re reserves of vile sees present in the soil. These onsist of new sees reently she y wee plnt s well s oler sees tht hve persiste in soil for severl yers (Mhmoo et l., ). The see nk is n initor of pst n present wee popultions. It hs een estimte tht only 1-9% of the vile sees proue in given yer evelop into seelings; the rest remin vile n ormnt tht my germinte in the susequent yers epening on the epth of uril. As result, wee see nks prove to e min soure of wees in griulturl fiels. Wees tht espe wee ontrol prtie proue thousns of sees, epening upon speies, n these sees re returne to the soil see nk n eome the soure of future wee popultion. Annul wees ehiit proigious see potentil thus proue smll superunnt sees (Sullivn, 1; Mrwt et l., 1). Wee sees re istriute oth horiontlly n vertilly in the soil profiles. See rin through vrious ispersl mehnisms is the min soure of see nk input. Similrly, germintion n emergene, physiologil eth, physil mge y implements s well s pretion re vrious uses of see losses from soil reserve. However, survivl n germintion of wee sees in the soil epens on the wee speies, epth of uril, soil type n tillge. Sees t or ner the soil surfe n esily e eten y inset, roents n irs. They my lso rot or germinte. On the other hn, urie sees re more protete from see eting nimls n re lso uffere from etremes of temperture n moisture (Sullivn, 1). The wee see nk in n griulturl fiel is me up of mny speies ut in given yer, the infesttion is typilly ominte y few speies. The speies tht ominte the infesttion re those est pte to urrent mngement prties n hve severl hrteristis tht ssure their survivl. Vriility of ispersl mehnisms, ormny uring unfvorle onitions n viility even fter long time uril llow wees to withstn unpreitle isturnes n hrsh limti onitions (Hrtler & Buhler, ). Whet is one of the mjor rops tht hve signifint eonomi n soil impt (Hll et l., 199; e l Fuente et l., 3). Being n griulturl ountry with mjor rle ln ultivte for this rop, Pkistn still hs to spen onsierle mount for whet import (Bkhsh et l., 6). The reson is minly ttriutle to ompetition from wees, whih seems to e one of the mjor ftors reuing rop yiel n frmers inome (Crmmer, 1967). Aven ftu L., Convolvulus rvensis L., Cyperus rotunus Pers., Fumri prviflor Lmk., Phlris minor Rit. n Solnum nigrum L. re mong noious wees ffeting whet fiels every yer espite of mngement prties (Bkhsh et l., 6). In eveloping ountries, suh s Pkistn, espite the vilility of high-teh solutions (e.g. seletive heriies n genetilly-moifie heriie-resistnt rops), the shre of rop yiel loss to wees seeme not to e reue signifintly over time (Cousens & Mortimer, 199). Moreover, heriies re rrely essile t resonle ost; hene frmers often nee to rely on lterntive methos for wee mngement.

2 1376 SEEMA MAHMOOD ET AL., Without the proper knowlege n tehnil ssistne, the strtegies they use hve the lest effet thus, wees remin the mjor use of yiel impeiments. In orer to meet the nees of growing popultion, the ountry requires lmost triple yiel from eisting frmln. For hieving this gol, we nee to voi those spets tht result in yiel loss prtiulrly wees. Therefore, the urrent stuy ws onute to investigte see nks of these wees from ifferent soil profiles. The im of this stuy ws to estlish the role of soil see reserves s soure of wee popultion n to suggest pproprite wee mngement n ontrol strtegies to minimie yiel losses ue to soil see reserves of the wee speies. Mterils n Methos Smpling ws one t the strt of the whet rop growing seson when previous rop ws remove n there h een no tillge prtie. The smpling sites were hosen in Distrit Vehri, Punj, (3 N, 7 E) euse of the ft tht whet is one the min rops grown there in rottion with otton. Moreover, this pttern of whet ultivtion ws eing followe t lest for lst yers t the stuy sites. Five whet fiels, eh hving n re of one re, were selete for smpling. Eh of the fiels ws ivie into equl plots n soil smples were tken from eh of these ifferent plots following Mhmoo et l., (). Using shrp knife, n re of 11 m ws mrke n 1 m eep ut ws given in the soil. Then thin setion of metl ws slippe uner the mrke squre n soil lok ws remove. Thus, totl of smples were ollete from fiels. Smple soil ore ws ivie into upper (-8 m) n lower (8-1 m) profiles n then trnsferre to lele pper gs. Germintion eperiment ws rrie out in plsti trys (61 m) for 6 weeks uner lortory onitions (1 C ±3) n wtere s n when neessry. The numer of vile sees ws quntifie vi seeling emergene from oth soil epths. The see nk sie (numer of sees/ m ) ws estimte for eh speies following Mhmoo et l., (). ANOVA (Generl Liner Moel) ws pplie to the t to revel vriility mong fiels, soil epths n speies using MINITAB version 14. Fisher s LSD (Lest Signifint Differene) multiple omprison test (Little & Jkson, 1978) ws use to eluite signifint ifferenes for mens vlues t p<.. Results n Disussion A signifint numer of sees of the speies were quntifie from oth soil profiles (Fig. 1). All sites were well ifferentite for see nks. Moreover, ifferentil istriution of wee sees etween the soil profiles lso eme evient from the sttistil nlysis (Tle 1). More seelings emerge from the eeper soil profile thn from the surfe. Thus, it eme ler tht the lower soil profile ontine greter numer of urie vile sees of the wees. Highest vlues for seeling emergene were oserve for C. rotunus from oth the soil profiles n more seelings emerge from the eeper soil lyer thn the surfe lyer (Fig. 1). It is evient from the t tht C. rotunus h the gretest overll see nk sie (numer of sees/ m ) tht ws signifintly ifferent from rest of the wees (p<.) (Fig. ). Moreover, the sie of see nk ws greter (4.6 sees/m ) in the eeper soil profile (8-1m) thn in the surfe lyer (3. sees/m ). C. rvensis h the seon highest vlue for sme ttriute followe y F. prviflor n A. ftu respetively (Fig. ). However, these speies i not iffer signifintly from eh other in see nk sie. No mrke ontrst ws oserve etween P. minor n S. nigrum s oth ehiite the lowest see nk sie for soil profiles (Fig. A). Though more see reserves for C. rvensis is surprising euse of lower feunity n lrger see sie of the speies ut still it seems tht seletion hs fvoure the superior see progeny y restriting their ispersl s ompre to lighter sees. Moreover, hnes of see loses of lrger sees ue to pretion re firly lesser s smller sees whih re preferentil prtiulrly for nts. A greter numer of see nk from eeper soil lyer (Figs. B & C) n e ttriute to mny resons. Firstly, the smpling ws rrie out prior to soil preprtion (ploughing or tillge) efore whet sowing thus urie sees were not epose to the soil surfe. Seonly, sees tht survive in eeper profiles re e to them over numer of yers thus the see nk represent wee popultion for the pst yers. Sine tillge prties efore sowing result reshuffling of soil then wee sees get fir hne of germintion n emergene thus using wee prolem (Clements et l., 1996). These finings re in line with Sullivn (1) who eperimentlly emonstrte tht see uril of rnyr grss n green fotil ws up to ten inhes ut the speies h shown 34-38% see germintion followe y igging n spreing of soil. On ontrry, only 1-% see germintion ws reore for sees tht were urie even up to n inh (.m). Another stuy (Hrrison et l., 7) lso epite onsistent reltionship etween see nk sie n epth of uril n regre it s suessful survivl strtegy euse sees ner the surfe re prone to more losses while, eep uril provie more protetion ut urie sees only germinte when they get epose to soil surfe y ny mens. Another importnt spet of wee survivl is geneti vriility euse see nks lwys ten to e potentil miture of mny genotypes n this store of hien geneti vrition provie rw mteril for seletion. As result, wees eome well pte n ompete with rop plnts. Furthermore, it is hr ft tht wee sees re present ll the times in soil s see nks. These n e ontrolle y limiting those onitions tht fvor see germintion n evelopment of wee seeling ohort. Sine see nk ehiit time ourse hnges, reflets the pst, present n future wee popultions thus it lso eomes importnt to limit ever inresing ontriutions of the wee sees in the form of soil nk for effetive wee mngement. Thus, preventing see set my not only enefit the urrent rop ut lso hve long term vntges. In ition, n integrte mngement pproh n work est to improve the sitution where onventionl frming prties re rrie out. Wee iology long with emogrphi pproh n ertinly provie more effiient wee mngement strtegies prior to wee see

3 PERSISTENCE OF SOME WEED SPECIES FROM WHEAT 1377 ispersl. Thus n integrte pproh must e emphsie to reue see nks (Lyon, & Dvi, 199). In this regr, n integrte knowlege of fertilier use, timing n frequeny of pre-sowing tretments n heriie pplition is very importnt n prove to e useful (Mrwt et l., 11). Applition of fertiliers ffet wee growth euse the entire wee ommunity is fertilie long with the rop uner suh situtions fertilier ne in rows will e ville to rop s propose y Swnton & Shresth (1). Stuies from Nersk (Wilson, 1996) suggeste tht y reuing wee A. Aven. ftu Seeling em erg ene B. Convolvulus rvensis Seeling C. Cyperus rotunus Seeling em eregene sees from the soil n use % eline in wee popultion just in single yer. Also, the rottion of rops n heriies n lso use shift in wee speies n knowlege of these shifts n help in hnging the omposition of the see nks from unesirle to esirle speies (Wilson & Furrer, 1996). Pre-irrigtion n stimulte the sees in the shllow one to germinte; the emerge seelings n e ontrolle n prevente from ompleting their life yle n prouing more sees (Swnton & Shresth, 1). D. Fumri prviflor 4 Seeling em erg ene 3 1 E. Phlris minor See lin g F. Solnum nigrum 3 Seeling m 8-1 m -8 m 8-1 m Fig. 1. (A-F): Distriution of see reserves of si wee speies (.6m ) estimte vi seeling emergene from two soil epths from five ifferent whet fiels (3 N, 7 E).

4 1378 SEEMA MAHMOOD ET AL., See nk sie/ m e e e f A.ftu C. rvensis C. rotunus F. prviflor P. minor S. nigrum See nk sie/m y A.ftu C. rvensis C. rotunus F. prviflor P. minor S. nigrum -8 m 8-1 m See nk sie/ m y -8 m 8-1 m Men vlues in eh figure shring the sme letters o not iffer signifintly y Fisher s multiple omprison test t.% proility level Fig.. (A-C): Intertive see nk sie (numer of sees/m ): speies fiels ross two soil epths (A), speies epths ross five fiels (B), fiels epths ross si speies (C).

5 PERSISTENCE OF SOME WEED SPECIES FROM WHEAT 1379 Tle 1. Anlysis of vrine for soil see nk of si wees estimte vi seeling emergene from two soil epths from five ifferent whet fiels (3 N, 7 E). Soures of vrition f Sum of squres Men squres F Speies *** * Depths *** Speies ** Speies Depths ** Depths * Speies Depths ** *,**,*** signifint t.,.1n.1proility levels Conlusions This stuy revele tht the soil see reserves re one of the min soures of wee infesttion in whet fiels. The sees n survive in the eep soil profile n ontriute onsierle vile reserves of the wee. Soil preprtion efore ultivtion rings out see trnsfer to the surfe n use onsierle wee germintion n growth. Our stuy suggests tht vrious frming n mngement prties shoul e synhronie to limit soil reserves of wee speies for effetive wee ontrol. Referenes Bkhsh, A., M. Hussin, A.A. Dsti, S. Mhmoo, M. Amin u Din n S.M.S. Nqvi. 6. Stuy of wees in whet fiels. Pk. J. Ari. Agri., 9(): Christensen, S. n T. Heisel Pth sprying using historil, mnul n rel-time monitoring of wees in erels. Zeitshrift fur Pflnenkrnkheiten n Pflnenshut. 4: 7. Clements, D.R., D.L. Benoit n C.J. Swntson Tillge effet on wee see return n see nk omposition. Wee Si., 44: Cousens, R. n M. Mortimer Dynmis of Wee Popultions. University Press, Cmrige, UK. Cousens, R.D Comprtive growth of whet, rley n nnul ryegrss (Lolium rigium) in monoulture n miture. Aust. J. Agri. Res., 47: Crmmer, H.H Plnt protetion n worl rop proution. In: The Biology of Wees. (E.): T.A. Hill. Ewr Arnol Lt, Lonon, pp e l Fuente, E.B., A. Susn, S.A. Sure n C.M. Ghers. 3. Wees n inset ommunities in whet rops with ifferent mngement prties. Agron. J., 9: Hll, A.J., C.M. Reell n G.J. Culot Fiel rop systems of the pmps. In: Fiel Crop Systems, Eosystems of the Worl. (E.): C.J. Person. Elsevier, Amsterm, The Netherlns, pp Gul, B., K.B. Mrwt, M. See n Z. Hussin 11. Impt of tillge, plnt popultion n mulhes on wee mngement n grin yiel of mie. Pk. J. Bot., 43 (3): Hrrison, S.K., E.E. Regnier, J.T. Shmoll n J.M. Hrrison. 7. See sie n uril effets on gint rgwee (Amrosi trifi) emergene n see memise. Wee Si., (1):16-. Hrtler, B. 4. Mnging wees to protet rop yiels. Wee Si., Iow stte University. ( ) Hrtler, B. n D. Buhler.. Fte of wee sees in the soil. Wee Si., Iow stte University. ( ) Lyon, J.D. n D. Dvi Cropping systems ontrol winter nnul grss wees in winter whet. J. Pro. Agri., 8(4): Lemerle, D., B. Vereek n N. Coomes Losses in grin yiel of winter rops from Lolium rigium ompetition epen on rop speies, ultivr n seson. Wee Res., 3: 3-9. Lemerle, D., B. Vereek n B. Orhr. 1. Rnking the ility of whet vrieties to ompete with Lolium rigium. Wee Res., 41: Little, T.M. n F.J. Hills Agriulturl Eperimenttion:Design n Anlysis. Wiley. Mrwt, K.B., S. Hshim n H. Ali. 1. Wee mngement: se stuy from North-West Pkistn. Pk. J. Bot., Speil Issue 4(1): Mrwt, K.B., M.A. Khn, S. hshim, K. Nw n K.M. Khttk. 11. Integrte wee mngement in whet. Pk. J. Bot., 43(1): Mhmoo, S., A. Ather n A.D.Q. Agnew.. Soil see nks n ispersl pttern of se rush, Junus mritimus in sptilly n temporlly isture ostl hitts. Phytologi, 87(3): -3. Smith, D.F. n G.R.T. Levik The effet of infesttion y Lolium rigium Gu. (nnul ryegrss) on yiel of whet. Aust. J. Agri. Res., : Sullivn, P. 1. Priniples of sustinle wee mngement for roplns. ATTRA, University of Arknss, Fyetteville. ( ) Swnton, C.J. n A. Shresth. 1. Tillge, soil type n wee see nk ynmis. Ontrio Corn Prouer, Mrh, 1. pp. 8. Wilson, R.G. n J. Furrer Where o wees ome from? University of Nersk-Linoln Coopertive Etension ( ) (Reeive for pulition 1 Otoer 1)